Pulmonary hypertension in patients with hemodynamically significant atherosclerotic lesion of a common carotid artery: new pathophysiological mechanisms of the disease

Abstract

Background. Pulmonary hypertension (PH) is a severe pathology that often leads a patient to death or disability. Recently, the development of PH associated with activation of the sympathetic nervous system (SNS) has been of interest. Some results obtained in an acute experiment on rats showed that activation of the carotid bodies of one external carotid artery is a sufficient stimulus to increase the tone of pulmonary arteries. Obviously, this effect is mediated by the sympathetic nervous system. However, the long-term effects of unilateral hypoxia of the carotid bodies on the morphofunctional state of the pulmonary arteries are not described in the literature.
 Aim. Effect assessment of common carotid artery bifurcation region ischemia due to the atherosclerotic process on the pulmonary arteries in patients.
 Materials and methods. The retrospective study was conducted in the Burdenko Neurosurgical Center and in the National Medical Research Center for Cardiology. A total of 60 case histories were analyzed in detail. All patients underwent Duplex scanning of the brachiocephalic arteries, as well as transthoracic echocardiography. The study included patients with atherosclerotic plaque in the area of the common carotid artery bifurcation on either one side or both. Exclusion criteria consisted of diseases that lead to the development of PH. The relationship between the presence of hemodynamically significant atheroma and the development of PH was evaluated.
 Results. Patients were divided into two groups those with hemodynamically significant atherosclerotic plaque in the common carotid artery bifurcation region at least on one side (more than 75% of the vascular obstruction) and hemodynamically insignificant atheromas in the common carotid artery bifurcation region on one or both sides (less than 45%). Among patients from the first group, 52.8% of the patients had signs of PH. Among patients from the second group, only 16.7% of the patients had signs of PH. The difference in the frequency of PH occurrence between the two selected groups is statistically significant (p=0.005). There were no differences in red blood cells number, platelets number, glucose concentration and lipid composition of blood plasma.
 Conclusion. Activation of SNS due to hemodynamically significant atherosclerotic plaque in the area of the bifurcation of the common carotid artery may be an independent mechanism for the development of PH.
 Key words: pulmonary hypertension, carotid bodies, atherosclerotic plaque, sympathectomy of pulmonary arteries.